The present invention relates to a transparent ocular lens material, and more particularly to an ocular lens material having excellent transparency, high oxygen permeability and high heat resistance (high glass transition temperature), and moreover having excellent ultraviolet-ray absorbing property and excellent forming and processing property, which is suitable for use as contact lenses, intraocular lenses, and the like.
Conventionally, for an ocular lens, especially for a contact lens, excellent oxygen permeability has been required as one of important physical properties because there is a necessity to supply a cornea with sufficient amount of oxygen through the ocular lens so that functions of metabolism of corneal tissue would not be lowered.
Also, for an intraocular lens, heat resistance has been required as one of important physical properties so that the intraocular lens can have sufficient heat resistance during autoclaved sterilization of the intraocular lens before inserting the intraocular lens into an eye.
Furthermore, a contact lens or an intraocular lens, in which an ultraviolet-ray absorbing agent is used, has been employed in order to avoid that bad influences owing to ultraviolet rays are exerted upon eyes. However, the contact lens or the intraocular lens, in which the ultraviolet-ray absorbing agents is used, especially the contact lens having high oxygen permeability, has a problem in safety that the ultraviolet-ray absorbing agent easily elutes from the lens.
Accordingly, it is desired that an ocular lens material which has transparency, improved oxygen permeability and heat resistance, and is excellent in ultraviolet-ray absorbing property is developed without using an ultraviolet-ray absorbing agent.
An object of the present invention is to provide an ocular lens material having excellent transparency and high oxygen permeability.
Another object of the present invention is to provide an ocular lens material having excellent forming and processing property as well as high heat resistance and excellent ultraviolet-ray absorbing property.
These and other objects of the present invention will become apparent from the description hereinafter.